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Four Basic Tissue Types:

• Epithelium• Connective Tissue• Muscle• Neural• Neural

CONNECTIVE TISSUEDiverse in structure and functionFound between other tissues (no apical surface)Specialized cells, spaced apartCells usu produce & maintain matrix (non-living portion)

1. CELLS• spaced apart• functionally specialized

“ li i ” ti2. MATRIX (produced by cells)

2 Components of CT:

Mesenchyme (embryonic connective tissue)

• “non-living” portion1. Extracellular protein fibers

(collagen, reticular, elastic fibers)

2. Ground substance (fluid)

• Support, surround, connect other tissues• Structural framework for body• Protect organs• Transport fluids and dissolved materials

St (f t) d i l

Some Functions of Connective Tissue:

• Store energy reserves (fat) and minerals• Immunity

1. Connective Tissue Propera. Mesenchymeb. Loose

• Areolar• Adipose

c. Dense• Regular• Irregular

2. Fluid Connective Tissue

OVERVIEWTypes of Connective Tissue

2. Fluid Connective Tissuea. Bloodb. Lymph

3. Supporting Connective Tissuea. Cartilage

• Hyaline cartilage• Fibrocartilage• Elastic cartilage

b. Bone

All connective tissue originates from MESENCHYME

(embryonic CT; stem CT cells)

BIO223: Human Anatomy L03: Connective Tissue, Muscle, and Nervous Tissue UNC-Asheville, f2011

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Tissue Matrix .

Fluid CT liquid

Three major categories of connective tissue (CT) are based on composition of the matrix

(non-cellular portion):

Fluid CT liquid

CT Proper semi-solid

Supporting CT solid

(1) Connective Tissue ProperMesenchyme Loose

• Areolar• Adipose

Dense

Connective tissue:

Dense• Regular• Irregular

(1) Fluid Connective Tissue

(2) Supporting Connective Tissue

CONNECTIVE TISSUE PROPER

Defined by matrix – density and orientation of fibers

Fibroblasts primary cell type secrete extracellular proteins (fibers)

Fibers:• collagen

long, straight, unbranched• reticular

thinner, flexible, branching• elastic

branched and wavy

fibroblasts

collagen

elastin

Loose Areolar Connective Tissue

• Areolar CT (“loose CT”)

fibers loosely arranged w/ lots of ground substance;provides flexibility; fills spaces bet. organs

Collagen fiberCollagen fiber

LOOSE connective tissues (“packing material”)

Elastic fibers

Fibroblasts

• Adipose (fat; cells = adipocytes)

cushions, protects; fills spaces; stores energyappears “empty” due to fat vacuolesfound below skin & throughout body

one adipocyte

LOOSE connective tissues (“packing material”)

fat-filled vacuole

nucleus

Areolar CT (“loose CT”)

LOOSE connective tissues (“packing material”)

Adipose (“fat”)

BIO223: Human Anatomy L03: Connective Tissue, Muscle, and Nervous Tissue UNC-Asheville, f2011

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Areolar tissue has adipocytes, and often blends into adipose tissue, based on increasing numbers of fat cells.

Adipose tissue appears to be made up almost entirely of adipocytes.

Areolar tissue

blending into

diadipose

adipose

(1) Connective Tissue ProperMesenchymeLoose

• Areolar• Adipose

Dense (“collagenous CT”)

Three major categories of connective tissue:

• Regular• Irregular

(2) Fluid Connective Tissue

(3) Supporting Connective Tissue

• Dense Regular CTcollagen fibers are parallel = ↑ strength in one directiontendons, ligaments

DENSE CT (semi-solid matrix w/ lots of fibers, esp. collagen)

fibroblasts

fibroblast

lagen

Dense Regular CT

fibroblast

• Dense Irregular CTcollagen fibers run in many directions; versatile strengthdermis of skin, capsules around joints, organs

DENSE CT (semi-solid matrix w/ lots of fibers, esp. collagen)

Collagenirregularly arranged

fibroblasts

(1) Connective Tissue Proper

(2) Fluid Connective Tissue• Blood• Lymph

(3) Supporting Connective Tissue

Three major categories of connective tissue:

(3) Supporting Connective Tissue

BIO223: Human Anatomy L03: Connective Tissue, Muscle, and Nervous Tissue UNC-Asheville, f2011

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FLUID CONNECTIVE TISSUE

• Liquid matrix• Contained within vessels

1. BLOODplasma (watery matrix)formed elements:

R d bl d ll ( th t )• Red blood cells (erythrocytes)• White blood cells (leukocytes) • Platelets

2. LYMPHformed from interstitial fluidlymph vessels, lymph nodeslymphocytes (types of WBC) – immunity

leukocyte

erythrocytes

platelet

Blood Vessel

(1) Connective Tissue Proper

(2) Fluid Connective Tissue

(3) Supporting Connective Tissue• Cartilage • Bone

Three major categories of connective tissue:

• Bone

SUPPORTING CONNECTIVE TISSUEStructural tissues – support and protectionSolid matrix, lots of fibers w/ few cells relative to matrix

Two main types

1. CARTILAGE2. BONE

Cells: CHONDROCYTES, found in LacunaeMatrix: solid/semi-solid (gelatinous)

Ground: chondroitin sulfatesFibers: collagen, elastic, reticular

Cartilage is avascular

CARTILAGE

Idealized diagram

3 types of cartilage:

1. Hyaline cartilage• widespread, common – articular surfaces on bone; embryonic skeleton; growth plates; trachea & larynx; attach ribs; parts of nose & ears• clear “glass” matrix (type II collagen) w/ cells in lacunae• strength, cushion, reduces friction – fibers not visible

Chondrocytesin lacunae

matrix

BIO223: Human Anatomy L03: Connective Tissue, Muscle, and Nervous Tissue UNC-Asheville, f2011

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2. Fibrocartilage(pubic symphysis, intervertebral disks, knee meniscus) – shock absorberfibrous matrix, cells in lacunaeresists compression, limits bone-bone contact

3 types of cartilage:

3. Elastic cartilage (earlobe, epiglottis, auditory tube)elastic fiber matrix; cells in lacunaeallows distortion but returns to original shape

3 types of cartilage:

BONECells: OSTEOCYTESGround: calcium salts, little fluidFibers: collagen

Bone has a well-developed blood supply.

Central canalContains blood vessels

Canaliculi

OsteocytesIn lacunae

Contains blood vessels

Four Basic Tissue Types:

• Epithelium• Connective Tissue• Muscle• Neural• Neural

MUSCLE TISSUEAll muscle tissue is specialized for contraction.

3 types of muscle tissue:• Skeletal • Cardiac • Smooth

BIO223: Human Anatomy L03: Connective Tissue, Muscle, and Nervous Tissue UNC-Asheville, f2011

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Skeletal Muscle• Found in “muscles” of the body• Voluntary control (nervous system initiates all contraction)• Striated; long worm-shaped fibers• Multiple nuclei per fiber

observe striations

fiber

nuclei

Cardiac Muscle• Heart (only)• Involuntary control• Constantly working; strong• Striations, branching• Single nucleus• Intercalated disks between cells

Smooth Muscle• wall of blood vessels, GI tract, bladder, etc.

(often around tubular organs) • Involuntary control• No striations; spindle-shaped• Single nucleus

Four Basic Tissue Types:

• Epithelium• Connective Tissue• Muscle• Neural (nerve tissue)• Neural (nerve tissue)

NERVE TISSUENervous tissue is specialized to conduct

electro-chemical impulses.Coordinate stimulus response

2 major cell types:• Neurons impulse-conducting cells• Neuroglia support cells (~5x more numerous)

neuron

neuroglia

Neurons

axon

dendrites

nucleus

Cartoon of a neuron

BIO223: Human Anatomy L03: Connective Tissue, Muscle, and Nervous Tissue UNC-Asheville, f2011

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REVIEW:Identify the tissues on the following slides

• To which of the 4 broad types does each belong?• Identify each tissue specifically.• Compare and contrast with other tissues shown.

REVIEW: Identify; Compare and Contrast

A B

Identify the tissues; compare and contrast them

A B

(1) Which specific cells are indicated?

C

Identify the tissues; Compare and contrast to the best of your ability

A B

Identify these four tissues

A B

DC

Identify these four tissues.

A

B

D

C

C, D are meant to be more challenging

BIO223: Human Anatomy L03: Connective Tissue, Muscle, and Nervous Tissue UNC-Asheville, f2011